Induction heating and control system and method with high reliability and advanced performance features
First Claim
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1. A method for sensing AC line voltage for an induction cooker, the method comprising sensing a voltage across a secondary winding of a flyback transformer.
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Abstract
An induction heating and control system and method have enhanced reliability and advanced performance features for use with induction cooking devices, such as induction heating ranges. Enhanced performance is facilitated via the use of an induction heating system which integrates voltage management, power management, thermal management, digital control sensing and regulation systems, and protection systems management.
71 Citations
72 Claims
- 1. A method for sensing AC line voltage for an induction cooker, the method comprising sensing a voltage across a secondary winding of a flyback transformer.
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12. A method for sensing AC line voltage for an induction cooker so as to facilitate operation of the induction cooker at full load, the method comprising:
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sensing a peak voltage across a winding of a transformer during a pulse;
storing the sensed voltage on a capacitor;
converting at least a portion of the voltage across the capacitor into a digital signal representative thereof; and
providing the digital signal to a microprocessor.
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13. A method for sensing AC line voltage for an induction cooker so as to facilitate operation of the induction cooker at full load, the method comprising:
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sensing a peak negative voltage across a secondary winding of a flyback transformer during a pulse width modulation (PWM) pulse;
rectifying the sensed voltage;
storing the rectified voltage on a capacitor;
dividing the voltage stored on the capacitor using a voltage divider that is connected to the capacitor and is connected to a regulated positive voltage source;
converting a divided portion of the voltage across the capacitor into a digital signal representative thereof; and
providing the digital signal to a microprocessor.
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14. A method of operating an induction cooker, the method comprising:
- sensing an AC line voltage provided to the induction cooker; and
automatically configuring the induction cooker to be operable at full load at the sensed AC line voltage.
- sensing an AC line voltage provided to the induction cooker; and
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15. A voltage sensing circuit for an induction cooker, the voltage sensing circuit comprising:
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a secondary winding of a flyback transformer;
a rectifier coupled to the secondary winding of the flyback transformer so as to rectify a voltage across;
a capacitor coupled to the rectifier so as to store the rectified voltage;
a voltage divider connected across the capacitor and connected to a regulated positive voltage source so as to divide the voltage stored on the capacitor;
an analog to digital converter coupled to the voltage divider so as to convert a divided portion of the voltage across the capacitor into a digital signal representative thereof; and
a microprocessor receiving the converted voltage, the microprocessor providing an output for effecting configuration of the induction cooker such that the induction cooker can operate at full load.
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16. A voltage sensing circuit for an induction cooker, the voltage sensing circuit comprising:
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a secondary winding of a flyback transformer;
a rectifier coupled to the secondary winding of the flyback transformer so as to rectify a voltage across;
a capacitor coupled to the rectifier so as to store the rectified voltage;
a voltage divider connected across the capacitor and connected to a regulated positive voltage source so as to divide the voltage stored on the capacitor;
an analog to digital converter coupled to the voltage divider so as to convert a divided portion of the voltage across the capacitor into a digital signal representative thereof; and
a microprocessor receiving the converted voltage, the microprocessor providing an output for effecting configuration of the induction cooker such that the induction cooker can operate at full load.
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17. A voltage sensing circuit for an induction cooker, the voltage sensing circuit comprising:
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a secondary winding of a transformer;
a rectifier coupled to the secondary winding of the flyback transformer so as to rectify a voltage thereacross;
a capacitor coupled to the rectifier so as to store the rectified voltage;
a voltage divider connected across the capacitor so as to divide the voltage stored on the capacitor;
an analog to digital converter coupled to the voltage divider so as to convert a divided portion of the voltage across the capacitor into a digital signal representative thereof; and
a microprocessor receiving the converted voltage, the microprocessor providing an output for effecting configuration of the induction cooker such that the induction cooker can operate at full load.
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22. An induction cooker having a voltage sensing circuit, the voltage sensing circuit comprising:
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a secondary winding of a transformer;
a rectifier coupled to the secondary winding of the flyback transformer so as to rectify a voltage across;
a capacitor coupled to the rectifier so as to store the rectified voltage;
a voltage divider connected across the capacitor so as to divide the voltage stored on the capacitor;
an analog to digital converter coupled to the voltage divider so as to convert a divided portion of the voltage across the capacitor into a digital signal representative thereof; and
a microprocessor receiving the converted voltage, the microprocessor providing an output for effecting operation of the induction cooker such that the induction cooker can operate at full load. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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23. A method for generating a high resolution, variable frequency waveform, the method comprising:
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providing an oscillator which is configured such that a frequency of an output thereof depends upon a resistance value; and
digitally switching a resistor network so as to vary a resistance provided thereby to the oscillator in a manner which varies the frequency of the output of the oscillator.
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30. A method for varying the amount of heat provided by an induction cooker, the method comprising:
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providing an oscillator which is configured such that a frequency of an output thereof depends upon a resistance value; and
digitally switching a resistor network so as to vary a resistance provided thereby to the oscillator in a manner which varies the frequency of the output of the oscillator.
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31. A high resolution, variable frequency waveform generator comprising:
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an oscillator which is configured such that a frequency of an output thereof depends upon a resistance value; and
a digitally switched resistor network coupled to the oscillator so as to vary a resistance provided to the oscillator in a manner which varies the frequency of the output of the oscillator. - View Dependent Claims (32, 33, 34, 35, 36, 37, 39, 40, 41, 42, 43, 44, 45, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 58)
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38. An induction cooker comprising:
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an oscillator which is configured such that a frequency of an output thereof depends upon a resistance value; and
a digitally switched resistor network coupled to the oscillator so as to vary a resistance provided to the oscillator in a manner which varies the frequency of the output of the oscillator.
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46. A method for cooking with an induction cooker, the method comprising:
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inductively applying power to a ferrous cooking container;
sensing a load of the applied power; and
adjusting the power applied based upon the sensed load such that a desired amount of power is applied to the cooking container.
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57. A method for cooking with an induction cooker, the method comprising:
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sensing a temperature of at least one location proximate the induction cooker; and
regulating power of the induction cooker so as to maintain a desired value for each sensed temperature.
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59. A method for cooking with an induction cooker, the method comprising:
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setting a temperature control to a temperature higher than a predetermined temperature limit;
inductively applying power to a cooking container, the inductively applied power being sufficient to heat the cooking container to the set temperature; and
after a predetermined length of time, reducing the power inductively applied to the cooking container so as to lower the temperature of the cooking container to a temperature below the predetermined temperature limit.
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60. A method for cooking with an induction cooker, the method comprising:
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determining a type of cooking intended by analyzing at least one of the power set by a user and the load provided by the cooking container and/or food being cooked; and
regulating cooking temperature so that cooking temperature is maintained within a safe (non-burning) limit with respect to the type of cooking determined.
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61. A method for cooking with an induction cooker, the method comprising:
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determining a type of cooking intended by analyzing a power setting which was set by a user and additional or no additional single input signals; and
regulating cooking temperature so that cooking temperature is maintained within a safe (non-burning) limit with respect to the type of cooking determined.
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62. A top for an induction cooker, the top comprising;
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a temperature resistant, substantially rigid material for supporting a cooking container during induction cooking; and
a temperature resistant, substantially flexible material disposed proximate the rigid material; and
wherein the flexible material is configured so as to inhibit spilled liquids from contacting electrical circuitry of the induction cooker if the rigid material cracks. - View Dependent Claims (63, 64)
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65. An induction cooker comprising;
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an induction coil;
electrical circuitry for effecting operation of the induction coil;
a temperature resistant, substantially rigid material for supporting a cooking container during induction cooking; and
a temperature resistant, substantially flexible material disposed proximate the rigid material; and
wherein the flexible material is configured so as to inhibit spilled liquids from contacting electrical circuitry of the induction cooker if the rigid material cracks. - View Dependent Claims (66, 67, 70, 71, 72)
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68. A barrier for an induction cooker, the barrier comprising;
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a heat resistant material configured to inhibit leaking of liquid thereby in the event that a support surface for cooking containers cracks;
wherein the barrier mitigates undesirable contact of the liquid with electrical circuitry.
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69. An induction cooker comprising:
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a support surface for supporting cooking containers during cooking;
at least one induction coil disposed generally below the support surface;
a light disposed proximate at least one of the induction coils; and
a light driver circuit configured to cause the light to illuminate in proportion to the power provided to the induction coil to which the light is proximate.
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Specification